9878721031 has 4 divisors (see below), whose sum is σ = 9880718872. Its totient is φ = 9876723192.

The previous prime is 9878721023. The next prime is 9878721077. The reversal of 9878721031 is 1301278789.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1301278789 = 37 ⋅35169697.

It is a cyclic number.

It is not a de Polignac number, because 9878721031 - 2³ = 9878721023 is a prime.

It is a super-2 number, since 2×9878721031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9878721001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 991485 + ... + 1001398.

It is an arithmetic number, because the mean of its divisors is an integer number (2470179718).

Almost surely, 2^9878721031 is an apocalyptic number.

9878721031 is a deficient number, since it is larger than the sum of its proper divisors (1997841).

9878721031 is a wasteful number, since it uses less digits than its factorization.

9878721031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997840.

The product of its (nonzero) digits is 169344, while the sum is 46.

The square root of 9878721031 is about 99391.7553472118. The cubic root of 9878721031 is about 2145.6896539388.

The spelling of 9878721031 in words is "nine billion, eight hundred seventy-eight million, seven hundred twenty-one thousand, thirty-one".